1. Field of the Invention
The present invention relates to an endoscopic treatment instrument adapted to be passed through a treatment instrument insertion channel of an endoscope, and in particular to a joint mechanism for connection between an manipulating section and a sheath of the endoscopic treatment instrument. The present invention also relates to an endoscopic treatment system using such joint mechanism.
2. Description of Related Art
In general, an endoscopic treatment instrument has a sheath, which is adapted to be inserted through an insertion channel of an endoscope, and a manipulation section for manipulating a treatment tool disposed at a distal end of the sheath. For efficiency in cleansing and disinfection of the instrument and replacement of a damaged sheath, it is desirable to incorporate a joint mechanism that permits the sheath to be separatable from the manipulating section. The joint mechanism should have a simple structure so as not to increase a manufacturing cost.
Japanese Utility Model Kokoku Publication No. Sho. 60-31684 discloses an example of the joint mechanism, in which a plastic member of a joint is split into sub-divisions by the provision of slits, and the sub-divisions are elastically deformed by a fastening ring to connect the sheath to the manipulating section. By loosening the fastening ring, the sheath can be disconnected from the manipulating section.
To achieve complete disinfection or sterilization after use of medical instruments, such medical centers recently increases that use an autoclave (i.e., a high-pressure steam sterilizer). In such medical centers, the treatment instruments are, in many cases, sterilized in a state that the sheath remains connected to the manipulating section.
If the plastic member in an elastically deformed state is subjected to a high-temperature and high-pressure environment of the autoclave, then the plastic member is plastically deformed into the elastically deformed shape, and thus the sheath cannot be disconnected from the manipulating section. In the case where the sheath is left for a long period of time while remaining connected to the manipulating section, the same problem arises.
Accordingly, an object of the present invention is to provide a joint mechanism for an endoscopic treatment instrument, which enables the separation between a sheath and a manipulating section and which is free from the deformation even when the sheath and the manipulating section are left for a long period of time while remaining connected together or when they are subjected to sterilization through use of an autoclave.
An endoscopic treatment system can be constructed using a joint mechanism such that various types of sheaths are provided, each having a respective medical treatment tool at its distal end, and the sheath sections are selectively connected to a common manipulating section according to the treatments required.
The common manipulating section in the above-mentioned endoscopic treatment system is provided with a high frequency power connection terminal to be connected to a high frequency power cord for a high frequency treatment instrument.
Since a metal is exposed on the surface of a sheath of a non-high-frequency (non-HF) treatment instrument, because of the high frequency power cord, the erroneous supply of a high frequency current during the use of the non-HF treatment instrument causes a danger. In general, an assistant prepares a medical treatment instrument, and therefore an accident may arise due to the insufficient communication between the assistant and a surgeon.
If the manipulating section of the high frequency treatment instrument is designed so as to completely preclude compatibility to the sheath of the non-HF treatment instrument, a probability of occurrence of an unforeseeable accident can be eliminated completely.
Even in such a case, a medical treatment instrument which is used both for a high frequency treatment and simply for collecting a tissue sample, e.g., so-called hot biopsy forceps, is used along with a high frequency treatment manipulating section even when the tissue sample is to be collected. There still remains a risk of electrical shock, which would be caused by erroneous application of a high frequency current.
Accordingly, another object of the present invention is to provide an endoscopic treatment system which ensures improved safety by eliminating the risk of electrical shock due to erroneous application of a high frequency current while reducing the number of kinds of manipulating sections.